CN113015921A

CN113015921A - Method for detecting a traffic participant

Info

Publication number: CN113015921A
Application number: CN202080005827.5A
Authority: CN
Inventors: R·蒙德
Original assignee: SMS Smart Microwave Sensors GmbH
Current assignee: SMS Smart Microwave Sensors GmbH
Priority date: 2019-05-06
Filing date: 2020-04-01
Publication date: 2021-06-22
Anticipated expiration: 2040-04-01
Also published as: WO2020224876A9; CN113015921B; WO2020224876A1; EP3857256A1; KR102661957B1; CA3116280C; KR20210065173A; CA3116280A1; EP3857256B1; US11320518B2; DE102019111679A1; JP7382659B2; JP2022504685A; US20210263134A1

Abstract

The invention relates to a method for detecting traffic participants along at least one traffic route, wherein the method comprises the steps of: transmitting a transmission signal by means of at least one transmitting device for radar radiation; to detect the received signal by at least one receiving device of , wherein the peak value of the detection matrix is assigned to the object; it is checked in a diagnostic module whether interference criteria are met; a signal is generated from the evaluation result in the evaluation module and the inspection result in the diagnostic module; and the signal is Transmission to the control module of the electronic data processing unit.

Description

Method for detecting a traffic participant

Technical Field

The invention relates to a method for detecting a traffic participant along at least one traffic route.

Background

Nowadays traffic participants are detected along various different traffic routes on land, on sea and in the air. This generally involves statistically assessing the number and type of traffic participants and/or controlling the flow of traffic along at least one traffic route.

Nowadays, the flow of traffic along traffic routes, in particular crossing traffic routes, such as intersections or entrances, is often controlled by electronically operated systems which, for example, adapt traffic light switches, priority driving rules and/or speed limits to the traffic conditions. For this reason, it is necessary to detect the current traffic situation. This is achieved in many cases by means of radar sensors which emit radar radiation in the form of a transmission signal, so that the transmission signal is reflected by the traffic participants, for example motor vehicles. The reflected radar radiation is detected in the form of a received signal. The received signal contains information about distance, radial speed, direction of motion and/or size of the traffic participant.

Various different forms of transmission signals are known from the prior art. For example, frequency ramps that are repeatedly and identically formed or differently formed and transmitted alternately or simultaneously may be used. Corresponding transmission signals are known, for example, from DE 102013008607 a1 and DE 102017105783 a 1. As the transmission signal, a signal generated by Phase Modulated Continuous Wave (PMCW) modulation, which is preferably digital, may be used. The signal is modulated in a phase-modulated manner onto a carrier wave, which can then be used as a transmission signal.

With today's methods it is possible to distinguish different types of traffic participants (for example motor vehicles, motorcycles and trucks) from one another, but also pedestrians or cyclists from one another and to control the flow of traffic on the basis of data saved for different types of traffic participants. This may include, for example, switching traffic light installations and/or opening or closing additional lanes or issuing or cancelling speed limits.

The use of radar sensors has the following advantages, for example compared to the use of cameras operating in the visible range: the radar sensor functions independently of sunlight and even in fog and darkness. However, even in the case of using radar sensors for monitoring and controlling traffic flow, interference may occur, for example, due to weather effects or interference with other radar radiation sources. In the case of a disturbance, the traffic participant cannot be detected, or at least cannot be detected optimally. Disturbances can obstruct or even prevent a clear flow of traffic and can also pose a danger especially for the relevant traffic participants.

Disclosure of Invention

The object on which the invention is based is therefore to improve the method for controlling the flow of traffic along at least one traffic route in such a way that disturbances are recognized early in the detection of traffic participants and can react, thereby increasing traffic safety.

The invention solves the stated object by means of a method for detecting a traffic participant along at least one traffic route, wherein the method comprises the following steps:

-transmitting a transmission signal by means of at least one transmission means for radar radiation;

-detecting a reception signal by means of at least one receiving device for radar radiation;

mixing the transmit signal and the receive signal to form a baseband signal, and calculating a detection matrix from the baseband signal and evaluating the detection matrix in an evaluation module of the electronic data processing device, wherein peaks of the detection matrix are assigned to the object;

-checking in a diagnostic module whether an interference criterion is fulfilled;

-generating a signal from the evaluation result in the evaluation module and the examination result in the diagnostic module; and

-transmitting the signal to a control module of the electronic data processing device.

Thus, according to the invention, the radar radiation is emitted in the form of a transmission signal by at least one transmitting device for radar radiation, which transmitting device is advantageously part of a radar sensor. As previously mentioned, these transmitted signals may have different forms. These transmitted signals are reflected with different intensities by different traffic participants located on the monitored subsections of at least one traffic route, wherein the intensity of the reflection depends, inter alia, on the size of the traffic participant and the distance of this traffic participant from the transmitting device and the receiving device. A part of the reflected radar radiation is reflected back in the form of a reception signal to the radar sensor, in particular to a receiving device for the radar radiation, which is the radar sensor part. The received signals are detected by means of at least one receiving device for radar radiation, which is preferably also part of the at least one radar sensor. The transmission signals emitted by the at least one transmitting device for radar radiation and the reception signals detected by the at least one receiving device for radar radiation are mixed to baseband signals, from which a detection matrix is calculated. For example, the detection matrix is a range-doppler matrix calculated from a double fourier transform of the baseband signal. The Range-Doppler matrix can also be calculated by correlation (Range) and fourier transformation (Doppler) if the transmitted transmission signal is not a repetitive frequency ramp, but, for example, a digital phase-modulated signal is preferred. This method is known from the prior art and is well known to the person skilled in the art. Other possible detection matrices are, for example, a range-time matrix or a range-angle matrix, in which only one fourier transformation is carried out. Preferably, a plurality of detection matrices are calculated and used in one measurement cycle, preferably in each measurement cycle, for example in different angular ranges and/or angular directions.

The detection matrix is then evaluated in an evaluation module of the electronic data processing device. In the detection matrix, spectral energy (signal energy) is assigned to different information. The distance ("range") is plotted on one axis of the range-doppler matrix, for example, and the doppler frequency and thus the information about the radial velocity of the traffic participant that will send a signal reflection is plotted on the other axis. Thus, the presence of signal energy which is preferably significantly higher than the matrix noise at the spectral position in the cells of the range-doppler matrix, particularly preferably more than 20dB higher than the matrix noise, means: the received signals result from reflections of the transmitted signals on objects, in particular traffic participants, which have a defined distance ("range") and a defined radial velocity towards or away from the at least one receiving device, which is derived from the respective doppler frequency. However, the assignment between radial velocity and doppler frequency may be ambiguous, for which methods for cancellation are known from the prior art.

The signal energy in such elements of the detection matrix, in particular of the range-doppler matrix, is referred to as "peak value", wherein different peak values of the range-doppler matrix are assigned to different objects, in particular to traffic participants. In this case, a single peak or a range doppler matrix with a plurality of peaks can be assigned to an object.

According to the invention, it is checked in the diagnostic module whether the interference criterion is fulfilled. Signals are then generated based on the evaluation of the detection matrix in the evaluation module and the examination in the diagnosis module, which are transmitted to the control module. Here, the evaluation result of the baseband signal in the time domain is preferably also taken into account.

For example, the control module is arranged to evaluate the signal and/or control the flow of traffic along at least one traffic route, e.g. in a statistical manner. In the latter case, a method is provided for controlling the flow of traffic along at least one traffic route.

Preferably, the evaluation module and/or the diagnostic module are part of an electronic data processing device which is part of a radar sensor which also has a transmitting device and/or a receiving device. Preferably, the control module is not part of a sensor, but of a control computer, for example for controlling the flow of traffic. Of course, the control module may also be part of the sensor. It is also possible that the evaluation module and/or the diagnostic module are not part of the radar sensor, but of another electronic data processing device, to which preferably also the control module belongs.

In a preferred embodiment, the evaluated detection matrix, preferably the evaluated range-doppler matrix, and the baseband signal are used to check whether the interference criterion is met. Advantageously, the interference criterion is fulfilled, for example, if rain and/or snow and/or interference with signals of other transmitting devices and/or a change in position and/or a change in orientation of the respective sensor is detected in the evaluation of the detection matrix.

Precipitation in the form of rain and/or snow also reflects at least a part of the transmitted signal emitted and in this way leads to a reception signal of a certain type. In the evaluated detection matrix, this leads to a characterized effect. Thus, for example, in the case of a Range-doppler matrix, a large amount of signal energy occurs at distances ("Range") of several meters, since a large part of the reflected transmission signal is reflected in this Range by a large number of precipitation elements, i.e. raindrops or snowflakes. Raindrops and snowflakes at large distances will not cause noticeable intensity of the received signal, although they will also reflect the transmitted signal penetrating thereto. The radial velocity of precipitation is also typical, as rain drops and snowflakes generally fall to the ground at a characteristic velocity. Depending on the wind conditions, the radial velocity towards or away from the at least one radar sensor will of course be affected. In this way, rain and/or snow can be detected easily and reliably.

If this is the case, the interference criterion is considered to be fulfilled, since it can no longer be achieved, or at least no longer reliably, for the sensor: the traffic participants are reliably and unambiguously identified and, if necessary, assigned to different categories.

Preferably, a plurality of detection matrices, preferably range-doppler matrices, of different, preferably successive measurement cycles are evaluated. These sounding matrices are formed from baseband signals that are a mixture of transmit and receive signals of different measurement periods. In this way, objects which are sought when evaluating a plurality of detection matrices can be correlated and the movement of the objects can therefore be tracked. As a result, a better distinction can be made between moving objects, in particular traffic participants, and static objects (for example buildings, signboards or traffic lights) than is possible by evaluating the radial speed. Thus, the moving object can be assigned an actual trajectory which contains, in particular, the positions of the respective object at different points in time. Advantageously, the interference criterion is considered to be fulfilled if a predetermined number (for example at least 10, at least 25 or at least 50) of these actual trajectories do not follow the trend saved in the electronic database. Preferably, these predetermined number of actual trajectories that do not follow the saved trend must occur within a predetermined time period (e.g., within 10 minutes, within 5 minutes, or within 2 minutes) to meet the interference criteria.

In general, a monitoring area of at least one traffic route is known, in which there may be traffic participants that can reflect the transmitted transmission signal in the direction of at least one receiving device. For example, the at least one traffic route has a plurality of lanes, in which the determined driving direction is dominant and which follow a predetermined course. The trend may be saved in an electronic database. The transmission of the transmission signal, the reception of the reception signal, the mixing of the signals into a baseband signal and the determination of the detection matrix, preferably the range-doppler matrix, and the evaluation of the detection matrix are generally carried out not only once, but a plurality of times one after the other, as described above. These method steps can be carried out, for example, several hundred times per second. Thus, a single object may be tracked over a longer period of time. In this case, the velocity vector and/or the location at which the respective object is detected may vary. In this way, the actual trajectory of the object and thus the trajectory of the traffic participant can be determined.

Preferably, this determined actual trajectory is compared with, for example, trajectories saved for different lanes of at least one traffic route. If the actual trajectory calculated from the different detection matrices deviates from the nominal trajectory stored in the electronic database, for example in azimuth or elevation, this is an obvious indication that the orientation and/or position of the at least one radar sensor has shifted, or that the position and/or orientation of at least one receiving device for radar radiation has shifted. The monitoring area of the traffic route changes in this way, so that reliable data can no longer be ascertained or at least cannot be ensured. Preferably, the interference criterion is fulfilled in this case.

Advantageously, the maximum signal-to-noise ratio, the minimum signal-to-noise ratio, the average signal-to-noise ratio and/or the median of the signal-to-noise ratios are found from the signal-to-noise ratios of the selected peaks of the detection matrix. The interference criterion is considered to be fulfilled if the maximum signal-to-noise ratio, the minimum signal-to-noise ratio, the average signal-to-noise ratio and/or the median of the signal-to-noise ratios are below a predetermined limit value. The predetermined limit value is, for example, 100dB, preferably 50dB, particularly preferably 20 dB. Thus, the corresponding signal-to-noise ratio is found by detecting selected peaks of a matrix, such as a range-doppler matrix. The maximum, minimum, mean and/or median of these ratios is then determined and compared with predetermined limit values. If the respective signal-to-noise ratio is less than a predetermined limit value, it is assumed that a reliable object recognition of the individual traffic participant cannot or cannot be reliably ensured in order to satisfy the interference criterion.

Preferably, the selected peaks of the detection matrix are all peaks that can be assigned to an object or a plurality of moving objects. In particular, all peaks that can be assigned to a moving object are preferred. Instead, the selected peaks are all the peaks of the detection matrix used.

In the evaluation of the detection matrix, for example the range-doppler matrix, a radar cross section of the object, preferably a moving object, is preferably determined. This can be determined, for example, from the strength of the received signals and the strength of the transmitted signals, wherein the distance and/or one or more angles of the respective object determined from the detection matrix are preferably also taken into account. In this embodiment of the method, the interference criterion is fulfilled if the maximum radar cross section, the minimum radar cross section and/or the mean radar cross section and/or the median value in the determined radar cross section is less than a predetermined limit value. For example, a typical value for a radar cross-section is about 1m for humans²About 10m for a passenger car²About 100m for a truck². Depending on the monitored cross-section, a predetermined limit value is selected for the average radar cross-section. If the respective limit value is undershot, then an interference criterion is present in the intermediate configuration of the method.

Preferably, the radar cross sections of all objects are determined, particularly preferably the radar cross sections of all moving objects are determined. Alternatively or in addition thereto, a radar cross section of a specific category of the object, for example of all passenger cars and/or all load carriers, can also be determined and used for the evaluation. In this case, different limit values can be used for the radar cross sections of different classes of objects.

In a preferred embodiment of the method, the at least one receiving device has a plurality of receiving antennas, preferably at least three receiving antennas, particularly preferably at least four receiving antennas, and further particularly preferably at least eight receiving antennas. The received signals reflected by the object arrive at these multiple receive antennas at different points in time. The received signals of the different receiving antennas are mixed with the transmitted signals and a detection matrix, for example a range-doppler matrix, is formed from the baseband signals thus produced. Due to the different points in time at which the received signals arrive at the different receiving antennas, phase shifts occur between the different received signals and thus different baseband signals are derived for different detection matrices. Complex-valued inputs with complex phases are generated in the fourier transformation carried out when calculating the detection matrix, in particular the range-doppler matrix. The phase difference of these phases between the two receiving antennas depends here only on their spacing. The pairs of receiving antennas having the same spacing also have the same phase difference.

Preferably, a measure for the dispersion of these phase differences is found, for example the standard deviation of these phase differences is found. The interference criterion is fulfilled if the maximum standard deviation, the minimum standard deviation and/or the mean standard deviation and/or the median of the standard deviations found exceed a predetermined limit value, which is, for example, 60 °, preferably 30 °, particularly preferably 5 °.

The standard deviation is preferably calculated for all peaks of the detection matrix, particularly preferably for the peaks that can be assigned to a subject. In a particularly preferred embodiment, the standard deviation of the phase difference is calculated for all peaks of the detection matrix that can be assigned to the moving object. Preferably, the calculation is performed in the azimuth direction and/or in the elevation direction. The azimuth angle extends in a plane perpendicular to the direction of gravity. And elevation angle describes the angle relative to the direction of gravity.

Preferably, the number of objects to which at least one peak of the detection matrix has been assigned is determined. Preferably, the number of static objects is determined. In this case, the interference criterion is considered to be fulfilled if the quantity exceeds a predetermined upper limit value, wherein the upper limit value is, for example, 150, preferably 100, particularly preferably 75, or if the quantity is below a predetermined lower limit value, wherein the lower limit value is preferably 10, preferably 20, particularly preferably 30. If the number of the determined objects to which at least one peak of the detection matrix can be assigned is greater than the predetermined upper limit value or less than the predetermined lower limit value, then: or this is a very unusual traffic situation for which there is no optimal control signal for controlling the traffic flow; or sensors which emit radar beams and receive received signals operate in an interfering manner. Of course, these limit values are selected according to the traffic route for which the traffic flow is controlled. In the case of rural roads which may be driven less, the predetermined upper limit value may be smaller, for example 50, 40 or 30, whereas in the case of large intersections of a plurality of traffic routes (for example a plurality of multi-lane roads), a larger upper limit value may be suitable, for example 200, 250 or 300. Likewise, in the case of rural roads that are likely to be driven less often, the predetermined lower limit value may be small, for example 5 or even 0. In the case of a large intersection of a plurality of traffic lines, a predetermined lower limit value of 40, 50 or 60 may also be suitable and may be selected.

If only static objects are counted or also static objects are counted, the respective limit value can be selected depending on the number of objects (e.g. signboards or buildings) actually present.

Advantageously, the characteristics of the baseband signals that characterize the interference disturbance are also investigated before the detection matrix, for example the range-doppler matrix, is calculated. Preferably, in order to identify these characterizing features: whether the signal energy and/or the signal amplitude exceed a predetermined or adaptively changed limit value. If an adaptively selected limit value is used, this limit value is advantageously adapted to the prevailing traffic situation, for example, by deriving the mean signal energy or the mean signal amplitude from the history (for this purpose, for example, a mean value calculation or a median calculation can be used) and determining the limit value, for example, by multiplying this value by 8, 10 or 12. Advantageously, the measure for determining the interference intensity and/or the frequency band occupied by the interference can be derived from an optional subsequent analysis of the exceeding of the limit values, for example in terms of position, width and/or variation over time. However, it is also possible to determine the interference intensity, for example, by observing an increased noise level after the first stage of fourier transformation or correlation or in the detection matrix. A sufficiently high interference intensity is then the interference criterion.

It is advantageous if the weighted sum of the maximum signal-to-noise ratio, the minimum signal-to-noise ratio, the mean signal-to-noise ratio and/or the median of the signal-to-noise ratio, the maximum radar cross section, the minimum radar cross section and/or the mean radar cross section and/or the median of the calculated radar cross sections, the minimum standard deviation, the maximum standard deviation and/or the mean standard deviation and/or the median of the calculated standard deviations and/or the number of objects and/or the interference strength exceeds a predetermined limit value, the interference criterion in the form of a total interference criterion is fulfilled. The limit value is almost freely selectable and can be shifted by suitable weighting of the individual summands. The predetermined limit value is for example-15, 10 or 100. To simplify the calculation, a single or all summands of the weighted sum may be set as a limit value or scaled separately if these summands exceed or fall below the limit value.

Thus, for example, if the maximum signal-to-noise ratio is below this value, the maximum signal-to-noise ratio may be increased to 5dB, 10dB, or 20dB or other suitable value. The maximum signal-to-noise ratio can also be set to 40dB, 50dB or 60dB if it exceeds this value, respectively. Preferably, the signal-to-noise ratio may also be limited to a range, e.g., 14dB to 50 dB. If a linear scale is used, the scale may be limited to 5 to 300. If the parameters are scaled individually, the range so limited is scaled to a scaling range of 0 to 100. Of course, other ranges and zoom ranges may also be used.

In this way, the calculation is simplified and errors due to values that are too large or too small are less likely to occur.

For example, the value of the minimum standard deviation can be set to 0rad, 0.1rad, or 0.2rad, or limited to a maximum of 0.75rad, 0.5rad, or 0.4 rad. This range may also be scaled to a scaling range of 0 to 100 for the weighted sum.

The number of possible objects may also be determined as a value, for example up to 60 and at least 0, wherein the range may also be scaled to a scaling range, for example 0 to 100. Advantageously, the parameter is defined as a predetermined limit value if the parameter exceeds or falls below a corresponding predetermined limit value.

Within the weighted sum, the signs of the respective weights can vary. Thus, for example, the minimum standard deviation is provided with a positive factor and the target number and maximum signal-to-noise ratio are provided with a negative factor. Of course, these factors may alternatively have respectively opposite signs.

Irrespective of whether the individual variables form the interference criterion individually or in the form of a weighted sum, these variables are preferably filtered in time, so that the evaluation results from a single detection matrix or a single measurement cycle do not immediately lead to an interference report or to the interference criterion being regarded as fulfilled. This can be achieved, for example, by a temporally floating average value, which is weighted if necessary, i.e. by the result of a plurality of preferably successive measuring cycles.

In a preferred embodiment, the at least one transmitting device for radar radiation and the at least one receiving device for radar radiation are each part of a radar sensor, wherein the position and/or orientation and/or the velocity and/or the acceleration of the radar sensor are advantageously determined by at least one additional (on-board) sensor. In order to obtain reliable measured values, it is necessary for the at least one radar sensor to maintain its set position and advantageously also its set orientation. If the position changes, for example because the utility pole or the sign plate to which the sensor is fastened is subjected to a traffic accident and, for example, falls over, it is no longer possible to ensure that the sensor monitors the desired region of at least one traffic route. This can be determined by means of a position sensor and/or an orientation sensor. Radar sensors are usually arranged above and/or beside the roadway, for example on utility poles, signboards or traffic light installations. In particular, traffic lights are often also arranged to be suspended above intersections, so that the traffic lights may swing due to wind. It can therefore be advantageous to use a speed sensor and/or an acceleration sensor in order to determine the speed and/or acceleration of the radar sensor and to consider the interference criterion as being met if a predetermined limit value is exceeded. Advantageously, there are position sensors, orientation sensors, velocity sensors and/or acceleration sensors for at least two, preferably all three, independent spatial directions.

Preferably, the interference criterion is fulfilled if the position and/or orientation and/or the speed and/or the acceleration of the radar sensor deviates from a nominal value by more than a predetermined limit value.

Advantageously, the control signal transmitted to the control module of the electronic data processing device is a number, position, velocity vector, dimension (spatial extension) and/or classification of the traffic participants (objects) that can be detected and derived from the peaks of the detection matrix, for example the range-doppler matrix, or a preliminary stage with information about distance, angle, radial velocity and/or other characteristics. The interference signal to be transmitted may contain the following information, for example: at least one radar sensor does not operate or operates unreliably. In this case, the control module of the electronic data processing device responsible for controlling the traffic flow would call up a traffic guidance and another possible time-controlled model of traffic flow control. Alternatively, however, the control signal may also contain information about that all lanes of at least one traffic route to be monitored are occupied, for example. In this case, it is advantageous if the number of traffic participants transmitted to the control module and the number of data of these traffic participants are overestimated, i.e. more traffic participants are reported than are actually present. For the case in which the interference criterion is regarded as fulfilled, therefore, as many traffic participants as possible in the lane and direction are reported.

Preferably, the signals generated from the evaluation result in the evaluation module and the examination result in the diagnosis module and then transmitted to the control module contain an evaluation signal which contains information about the object sought when evaluating the range-doppler matrix if the interference criterion is not met. Preferably, the signal consists of an evaluation signal when the interference criterion is not fulfilled. For example, the evaluation signal contains, for example, a list of all peaks in the evaluation of the range-doppler matrix, in which, for example, the radial velocity and the distance to the radar sensor and, if appropriate, the properties of the respective object or of a plurality of objects are contained. The evaluation signal may also comprise an occupancy signal of the virtual induction loop, by means of which the determined lane is indicated to a control module of a control computer, for example for controlling the switching of traffic light installations at intersections. The evaluation signal may also contain a trigger signal, which, for example, warns of a rapidly approaching traffic participant.

Preferably, in addition to the evaluation signal, the signal also contains a diagnostic signal containing the following information: the interference criterion is not met.

Preferably, the signal comprises a diagnostic signal which, when the interference criterion is fulfilled, comprises the following information: the interference criterion is met. The diagnostic signal may consist of the information only. Instead, the diagnostic signal contains information about the cause of the interference. This is possible in particular when different interference criteria are present, of which only one or a small number are met. In this way, different causes of interference, such as rain, snow, storms or movement of the sensor, can be distinguished. Furthermore, the diagnostic signal may comprise a contribution of the disturbance. Thus, for example, the field of view of the radar sensor may be limited by rain, so that although reliable data can still be generated and transmitted to the control module, these data are nevertheless reliable only for a limited distance from the radar sensor. For example, the diagnostic signal may contain the following information: the field of view of the radar sensor is limited to a certain fraction, for example 75%, 50% or 25%, by rain or snow.

Preferably, the signal comprises an evaluation signal relating to a fictive target when the interference criterion is fulfilled. Thus, for example, the evaluation signal can contain the following information: all lanes are occupied, although this cannot be derived from the evaluation of the range-doppler matrix due to interference. This is advantageous in particular if the control module is part of a control computer which is able to control, for example, a traffic guidance or a traffic flow on at least one traffic route using only the respective evaluation signal. In particular, the old control computer is not provided for obtaining diagnostic signals in addition to these evaluation signals in order to know the functional disturbance of the radar sensor.

Preferably, a plurality of radar sensors, for example four radar sensors, are used in the method. These radar sensors are preferably arranged at intersections where at least two traffic routes intersect or cross. In this case, the four sensors monitor, for example, different sections of the traffic route or different traffic routes. The transmitted and received signals of all radar sensors are processed into a range-doppler matrix and evaluated. The evaluation signal is transmitted to an intersection computer containing a control module. If desired, the diagnostic module is also part of the intersection computer. This is however not necessary, as the diagnostic module may also be arranged in one or each radar sensor.

In a particularly preferred embodiment, a plurality of sensors is used in the method. In this way, different parts of the traffic route and/or different traffic routes can be monitored and the traffic participants located thereon can be detected. Preferably, in this case, the transmission signal is transmitted by each of the sensors, and the reception signal is received by each of the sensors. Preferably, in this case, the control module is part of the control computer. Preferably, this also applies to the diagnostic module, which preferably evaluates the detection matrix generated and provided by all sensors and corresponding signals.

In the evaluation module, a list of all objects is preferably created, which can each be assigned at least one peak of the detection matrix. Additionally or alternatively, an occupancy signal for the virtual induction loop or other trigger signal required or at least helpful to control traffic flow is generated. Including signals containing information about rapidly approaching objects and the like.

Preferably, the diagnostic module generates a diagnostic signal which may contain, for example, the following information: one or all of the sensors used are disturbed. Additionally, the degree of interference and/or the cause of the interference may be accounted for. Such information may include, for example: the sensor is 35% disturbed due to a first disturbance cause, for example rain.

The invention also solves the problem set forth by a sensor for detecting a traffic participant along at least one traffic route, wherein the sensor is provided for carrying out a method according to one of the embodiments described herein. The sensor preferably has an electronic data processing device with an evaluation module and preferably a diagnostic module.

Drawings

Embodiments of the invention are explained in detail below with the aid of the figures. The figures show:

FIG. 1 is a schematic diagram of an apparatus according to one embodiment of the present invention;

FIG. 2 is a schematic evaluation according to distance from an object;

FIG. 3 is a schematic evaluation of radial velocity and reflectivity from an object;

figure 4 is a schematic diagram of a check interference criterion.

Detailed Description

Fig. 1 schematically shows a radar sensor 2 having a transmitting device 4. The transmitting means 4 are arranged for transmitting a transmission signal 6. In fig. 1, these transmitted signals are reflected by the traffic participant 8 and in the form of received signals 10 in the direction of the radar sensor 2. The traffic participant 8 may be, for example, a pedestrian, a rider, a passenger car, a truck or another traffic participant.

The radar sensor 2 has a receiving device 12, which is provided for detecting the received signal 10. In the exemplary embodiment shown in fig. 1, the radar sensor also has an electronic data processing device 14. The electronic data processing device has an evaluation module 16 and a diagnostic module 18. It is advantageous, but not absolutely necessary, for the evaluation module 16 and the diagnostic module 18 to be part of the same electronic data processing device 14, or for the electronic data processing device 14 to be part of the radar sensor 2.

The received reception signal 10 is supplied by the receiving device 12 to an evaluation module 16. Where a detection matrix is calculated and evaluated. In the diagnostic module 18 it is checked whether the interference criterion is fulfilled. Subsequently, signals are generated from the evaluation result in the evaluation module 16 and the examination result in the diagnostic module 18, which are transmitted to a further electronic data processing device 20. The further electronic data processing device has a control module 22 to which signals are transmitted along a data connection 24. The control module 22 of the electronic data processing device 20 is provided for controlling the flow of traffic along a traffic route, for example, by switching traffic light installations, traffic signs or taking other measures which influence the flow of traffic.

In a preferred embodiment, the electronic data processing device 20 is also part of the radar sensor 2. It is particularly preferred that the electronic data processing device 14 and the electronic data processing device 20 are the same electronic data processing device, so that the evaluation module 16, the diagnostic module 18 and the control module 22 are part of a single data processing device.

Fig. 2 shows the evaluation of the detection matrix, wherein the distance (Range) is plotted for different measurement periods. A large number of identified objects are visible within a small distance of up to 25 meters from the sensor, which objects are shown in black for better clarity. White boxes shown in dashed lines mark these objects. It can therefore be determined from the evaluation of the distance that in the exemplary embodiment shown, a large number of objects are present at a very small distance from the actual sensor.

Fig. 3 shows a further evaluation of the detection matrix or a further part of the evaluation of the detection matrix. The radial velocity, i.e. the velocity of the object towards or away from the sensor, is shown in the upper region. Here, a large number of objects also exist in the range of low speed. The relevant speed range of an object having a radial speed of, for example, less than 10m/s is again highlighted by a dashed box shown in white.

In the lower region of fig. 3, the reflectivity, which is a direct measure for the radar cross section of the object, is plotted for a large number of different measurement periods. Here, it can also be seen that the object is less than 0dBm at the radar cross section²Is aggregated in the range of (1). The results of the three diagrams in fig. 2 and 3 therefore allow to recognize a plurality of objects with a very small radar cross section, which are located within a small distance from the sensor and have a small radial velocity. In the illustrated embodiment, the object can be recognized as rain.

However, it is decisive here for the functional capability of the sensor that the rain has a defined strength. This can be found by: a single "rain object" that can be extracted from the evaluation of fig. 2 and 3 is counted. If the number of rain objects thus determined exceeds a predetermined limit, it is assumed that the rain is so great that the functional capability of the sensor is impaired. This can be taken from fig. 4. The limit value set in the example shown is 100 objects. If more objects are detected, the line shown in blue is above the set limit value and the functional capability of the sensor must be considered limited. In the embodiment shown, this is the case, for example, until measurement period 2450. If the number of counted rain objects is below a limit value, the functional capability of the sensor is not limited, so that the interference criterion is not fulfilled. In the embodiment shown in fig. 4, the interference criterion is met between measurement periods 72 to 2450 and 3054 to 3267, but not during and after.

List of reference numerals

2 radar sensor

4 transmitting device

6 sending signals

8 traffic participants

10 receiving a signal

12 receiving device

14 electronic data processing device

16 evaluation module

18 diagnostic module

20 electronic data processing device

22 control module

24 data connection

Claims

1. A method for detecting a traffic participant along at least one traffic route, wherein the method has the following steps:

-mixing the transmit signal and the receive signal to a baseband signal, and calculating a detection matrix from the baseband signal and evaluating the detection matrix in an evaluation module of an electronic data processing device, wherein a peak of the detection matrix is assigned to an object;

-transmitting said signal to a control module of an electronic data processing device.

2. Method according to claim 1, characterized in that an interference criterion is fulfilled if rain and/or snow is detected when evaluating the detection matrix.

3. Method according to claim 1 or 2, characterized in that a plurality of detection matrices are evaluated one after the other, so that an actual trajectory can be assigned to the object and the interference criterion is fulfilled if a predetermined number of actual trajectories do not follow the course (nominal trajectory) stored in the electronic database.

4. Method according to any of the preceding claims, characterized in that a maximum signal-to-noise ratio, a minimum signal-to-noise ratio, a mean signal-to-noise ratio and/or a median of the signal-to-noise ratios is/are derived from the signal-to-noise ratios of the selected peaks of the detection matrix and an interference criterion is fulfilled if the maximum signal-to-noise ratio, the minimum signal-to-noise ratio, the mean signal-to-noise ratio and/or the median of the signal-to-noise ratios is/are below a predetermined limit value, wherein the predetermined limit value is preferably 100dB, preferably 50dB, particularly preferably 20 dB.

5. Method according to one of the preceding claims, characterized in that in the evaluation of the detection matrix a radar cross section of the selected object, preferably of the selected moving object, is ascertained and in that an interference criterion is fulfilled if the median of the maximum radar cross section, the minimum radar cross section and/or the mean radar cross section and/or the ascertained radar cross section is less than a predetermined limit value.

6. Method according to one of the preceding claims, characterized in that the at least one receiving device has a plurality of receiving antennas, preferably at least three receiving antennas, and that the standard deviation of the phase difference between each two receiving antennas, preferably in the azimuth direction and/or the elevation direction, is calculated for a selected peak or a selected object, and that an interference criterion is fulfilled if the maximum standard deviation, the minimum standard deviation and/or the mean standard deviation and/or the median of the calculated standard deviations exceed a predetermined limit value, wherein the predetermined limit value is preferably 60 °, preferably 30 °, particularly preferably 5 °.

7. Method according to one of the preceding claims, characterized in that the number of objects to which at least one peak of the detection matrix has been assigned is determined and an interference criterion is fulfilled if the number exceeds a predetermined upper limit value, wherein the predetermined upper limit value is, for example, 150, preferably 100, particularly preferably 75, or if the number is below a predetermined lower limit value, wherein the predetermined lower limit value is preferably 10, preferably 20, particularly preferably 30.

8. Method according to any of the preceding claims, characterized in that an interference criterion is fulfilled if the interference strength of a received signal which is not composed of a reflected transmitted signal exceeds a predetermined limit value.

9. The method according to any one of claims 3 to 8, wherein if, the method is applied to a patient

-the maximum signal-to-noise ratio, the minimum signal-to-noise ratio, the average signal-to-noise ratio and/or a median of the signal-to-noise ratios,

-the median of the maximum radar cross-section, the minimum radar cross-section, the average radar cross-section and/or the radar cross-section,

-the maximum standard deviation, the minimum standard deviation, the mean standard deviation and/or the median of the standard deviations,

-deviation of the actual trajectory from a nominal trajectory,

Interference intensity and/or

-the weighted sum of the number of objects exceeds or falls below a predetermined limit value, an interference criterion is fulfilled.

10. Method according to any of the preceding claims, characterized in that the at least one transmitting device and the at least one receiving device are part of a radar sensor and the position and/or orientation and/or velocity and/or acceleration of the radar sensor is determined by at least one sensor.

11. Method according to claim 9, characterized in that an interference criterion is fulfilled if the position and/or orientation and/or the speed and/or the acceleration of the radar sensor deviates from a nominal value by more than a predetermined limit value.

12. The method according to any of the preceding claims, characterized in that the signal comprises an evaluation signal, which contains information about an object sought when evaluating the detection matrix, when an interference criterion is not fulfilled.

13. The method according to claim 11, characterized in that in addition to the evaluation signal, the signal also contains a diagnostic signal containing the following information: the interference criterion is not met.

14. The method according to any of the preceding claims, wherein the signal comprises a diagnostic signal comprising the following information when an interference criterion is fulfilled: an interference criterion is fulfilled, wherein the signal preferably does not contain information about the object.

15. Method according to any of the preceding claims, characterized in that the signal contains an evaluation signal about a fictitious object when an interference criterion is fulfilled.

16. A sensor for detecting traffic participants along at least one traffic route, wherein the sensor is arranged for carrying out the method according to any one of the preceding claims.

17. Sensor according to claim 16, characterized in that the sensor has an electronic data processing device with an evaluation module and preferably a diagnostic module.